Occultibambusa kunmingensis C. X. Liu, H. Zhang & K. D. Hyde

Ren, Guang-Cong, Tibpromma, Saowaluck, Dong, Kai-Xuan, Gao, Chen-Xi, Zhang, Chao-Shan, Karunarathna, Samantha C., Elgorban, Abdallah M. & Gui, Heng, 2024, Unveiling fungi associated with Castanopsis woody litter in Yunnan Province, China: Insights into Pleosporales (Dothideomycetes) species, MycoKeys 108, pp. 15-45 : 15-45

Occultibambusa kunmingensis C. X. Liu, H. Zhang & K. D. Hyde , Fungal Diversity 105: 471.

Fig. 6

Description.

Saprobic on dead twigs of Castanopsis delavayi ( Fagaceae ) in terrestrial habitat. Sexual morph: Ascomata 160–180 μm high, 160–240 μm diam. (x ̄ = 175 × 195 μm, n = 5), dark brown to black, solitary or gregarious, semi-immersed to superficial, coriaceous, subglobose, with a short papillate, ostiolate. Ostioles 50–65 µm long, 35–40 μm diam., black, short. Peridium 20–35 μm thick, thin at the base and becoming wider laterally, composed of several layers of brown to dark brown, thick-walled cells of textura angularis. Hamathecium 2.5–3.5 µm wide, hyphae-like, septate, cellular pseudoparaphyses, embedded in a gelatinous matrix. Asci (60) 74–107 (– 116) × 12–14 μm (x ̄ = 82 × 13 μm, n = 20), 8 - spored, bitunicate, fissitunicate, clavate or cylindric-clavate, narrowly rounded at the apex, with a short truncate pedicel, apically rounded, with a minute ocular chamber. Ascospores 30–40 × 4–6 μm (x ̄ = 35.6 × 5.3 μm, n = 20), overlapping 1–2 - seriate, fusiform, straight or slightly curved, 1 - septate, brown, constricted at the septa, guttulate, thin and smooth-walled, without mucilaginous sheaths and appendages. Asexual morph: Undetermined.

Culture characteristics.

Ascospores germinated on PDA within 24 h at room temperature (25 ° C). Germ tubes produced from the basal and apical cells of ascospore. Colonies on PDA, reaching 25 mm diameter after 2 weeks at 20–25 ° C, mycelia superficial, dense, circular, raised, entire edge, velvety, flossy; reverse black.

Material examined.

China, Yunnan Province, Baoshan (25 ° 18 ' 48 " N, 99 ° 09 ' 50 " E) on dead woody twigs of Castanopsis delavayi ( Fagaceae ), 12 July 2020, G. C. Ren, BS 17 ( HKAS 122706 ), living culture KUNCC 21-0506 .

Known host, habitats, and distribution.

Bamboo and Castanopsis delavayi from freshwater and terrestrial in China ( Dong et al. 2020; Jiang et al. 2021; this study).

Notes.

According to the multi-gene phylogenetic analyses of combined SSU, LSU, ITS, tef 1 - α, and rpb 2 sequence dataset, our new isolate (KUNCC 21-0506) nested with Occultibambusa kunmingensis (HKAS 102151), which was isolated from decaying bamboo submerged in freshwater in China ( Dong et al. 2020) with 100 % ML and 1.00 BYPP bootstrap support (Fig. 2 ). Our new isolate fits well with the morphological characteristics of the holotype of O. kunmingensis in having semi-immersed to superficial ascomata with short papillate, clavate or cylindric-clavate asci, fusiform, 1 - septate, brown ascospores without mucilaginous sheaths and appendages ( Dong et al. 2020). Sequence comparison for the ITS and tef 1 - α region between our isolates (KUNCC 21-0506) and O. kunmingensis (HKAS 102151) showed no significant base pair differences. Therefore, we identified our taxon as a new host record of O. kunmingensis from Castanopsis delavayi ( Fagaceae ) in China, and it is the first record from woody litter.

Figures

Figure 2. Phylogram generated from maximum likelihood analysis based on the combined SSU, LSU, ITS, tef 1 - α, and rpb 2 dataset of Occultibambusaceae species. Related sequences were obtained from Yu et al. (2022). Bootstrap values for ML are equal to or greater than 75 %, and posterior probability values are equal to or greater than 0.95 from the BYPP analysis labelled on the nodes. Strains of the newly described species are in red, while type strains are in bold. The tree is rooted with Ernakulamia krabiensis (MFLUCC 18-0237) and E. xishuangbannaensis (KUMCC 17-0187).

Figure 6. Occultibambusa kunmingensis (HKAS 122706) a host b ascomata on host surface c vertical section of ascoma d peridium e pseudoparaphyses f – j asci k – m ascospores n germinated ascospore o, p colonies on PDA (o = from above, p = from below). Scale bars: 100 µm (c); 20 µm (d – j); 10 µm (k – n); 20 mm (o, p).